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Abstract:

There is provided a method for air-tightly enclosing a pellicle case in a
filmy bag which protects the pellicle case against dust without the use
of a plurality of bags or without modifying the filmy bag except for
folding it like origami and eventually consolidating with an adhesive
material: in short the opening of the bag is folded a number of times
compactly.

Claims:

1. A method for air-tightly containing in a film bag a flat product
comprising steps of: inserting, within a clean room, the product into the
bag and then folding that part of the bag which includes the opening two
or more times in a same direction and consolidating the folded bag with
an adhesive means thereby preventing unfolding of the bag.

2. A method for air-tightly containing in a rectangular film bag a flat
product having at least one pair of parallel sides comprising steps of:
(i) inserting, within a clean room, the product into the bag in a manner
such that one of the parallel sides of the product comes to a bottom end
side of the bag, (ii) folding the bag over a line that runs equidistant
from the open end side of the bag and the other one of the parallel sides
of the product, (iii) folding the bag in the same direction as in the
step (ii) over a line that runs equidistant from the line over which the
bag has been folded immediately previously and said the other one of the
parallel sides of the product, this step being conducted at least one
time, and (iv) consolidating the folded bag with an adhesive means
thereby preventing unfolding of the bag.

3. A method as claimed in claim 2, wherein before the step (iv) said bag
is folded in the same direction as in the step (ii) over said the other
one of the parallel sides of the product.

4. A method as claimed in claim 2, wherein said step (iii) is conducted
no more than four time.

5. A method as claimed in claim 2, wherein said product is a case
containing a pellicle.

6. A pellicle kit consisting of a pellicle and a pellicle case containing
said pellicle and a film bag containing said pellicle case, wherein said
film bag air-tightly contains said pellicle case in either of the manner
as described in claim 2.

Description:

[0001] The present non-provisional application claims priority under 35
U.S.C. §119(a) from Japanese Patent Application No. 2010-112917
filed on May 17, 2010, the entire disclosure of which is hereby
incorporated by reference.

FIELD OF THE INVENTION

[0002] This invention relates to a method for hermetically enclosing in an
air-tight bag a product (especially an encased pellicle), the
manufacturing of which is completed in a clean room.

TECHNICAL BACKGROUND OF THE INVENTION

[0003] A product of which the manufacturing process is completed in a
clean room, for example a pellicle (hereinafter when the explanation only
refers to a pellicle, it should be taken as an example representing other
such products), often ends up with being contained in a container
specially designed for the particular product, such as a pellicle case;
however, if the container is brought out of the clean room as it is, the
container is liable to attract the dust in the air so that when the
container is brought into a clean room and opened for the removal of the
pellicle, the pellicle may collect some of the dust from the container
and some other part of the dust may soil the clean room as well.

[0004] Hence, a pellicle encased is usually shipped, on account of this
fact, after being wrapped in two or more bags made of an air-tight film
material, the innermost bag containing the encased pellicle and being
inside the next innermost bag and so on, so as to avoid dust, and when,
for example, a pellicle is to be brought in a clean room for use, the
outermost bag is removed immediately before the bagged pellicle is
brought into the clean room.

[0005] In order to keep clean a pellicle manufactured in a clean room as
well as its container, it is necessary to pack them with a careful
attention, and to this end, heretofore, a packing bag has been
hermetically closed by being sealed with heat, or has been provided with
a zipper (such as a rail fastener) for secure closing, or has had its
mouth completely sealed with an adhesive tape. Furthermore, two or more
of these procedures have been combined to achieve a perfectly sealed
packaging for shipment.

[0006] However, while the product is safe from being contaminated thanks
to the faultless packaging, the multi-bag packaging, especially when the
number of the bags exceeds three or four, renders the opening operation
troublesome and in a case where a bag is thermally sealed, a person
opening the package must use a pair of scissors or a knife so that extra
tools are in need and what is more the cut face would become a new source
of contaminant particles. Also, in the case of a bag with a zipper, the
cost is increased and the zipper would allow some foreign particles to
pass through it.

SUMMARY OF THE INVENTION

Problems the Invention Seeks to Solve

[0007] In view of the above circumstances, it is an object of the present
invention to provide a method for hermetically enclosing a product in a
package bag whereby foreign materials are shut out, no extra tools to are
required, and the retrieval of the product from the package is easy.

Means to Solve the Problems

[0008] One aspect of the method according to the present invention, which
is for air-tightly containing in a film bag a flat product within a clean
room, comprises the steps of inserting the product into the bag and then
folding that part of the bag which includes the opening two or more times
in a same direction and consolidating the folded bag with an adhesive
means thereby preventing unfolding of the bag.

[0009] Also the method according to the present invention for air-tightly
containing in a rectangular film bag a flat product having at least one
pair of parallel sides comprises the steps of:

(i) inserting, within a clean room, the product into the bag in a manner
such that one of the parallel sides of the product comes to a bottom end
side of the bag, (ii) folding the bag over a line that runs equidistant
from the open end side of the bag and the other one of the parallel sides
of the product, (iii) folding the bag in the same direction as in the
step (ii) over a line that runs equidistant from the crease line over
which the bag has been folded immediately previously and said the other
one of the parallel sides of the product, this step being conducted at
least one time, and (iv) consolidating the folded bag with an adhesive
means thereby preventing unfolding of the bag.

What is Achieved by the Invention

[0010] As the result of the invention, it has become possible to open and
close a hermetic film bag with ease and convenience in a manner such
that, when closed, no atmospheric air can enter the bag and, when being
opened, there is no need for an extra device to open it and thus no worry
for contaminants from such a device, although the opening and closing
operation is done merely by folding and unfolding the bag.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a pair of drawings in sequence which illustrates how a
bag for an encased pellicle is first folded, showing the line over which
the first folding is done in broken line and the direction in which the
folding is done by a curved arrow.

[0012] FIG. 2 is a pair of drawings in sequence which illustrates how the
bag is secondarily folded, showing the line over which the second folding
is done in broken line and the direction of the secondary folding by a
curved arrow.

[0013] FIG. 3 is a drawing which illustrates how the bag is tertiarily
folded, showing the line over which the tertiary folding is done and the
direction of the tertiary folding by a curved arrow.

[0014] FIG. 4 is a drawing illustrating how the bag may be consolidated
after the foldings with an adhesive tape, which is the final step of the
method of the invention.

EMBODIMENT OF HOW THE INVENTION IS CARRIED OUT

[0015] The present invention relates to a convenient and piece-of-cake
method for closing an open end side of a loaded bag without using a heat
sealing or a zipper or the like, and with the result that the closing and
opening operation can be conducted in a brief time and the bag is safe
from the entrance of foreign material while closed or while being opened;
in particular, the bag's open end side is folded three or more times
before the folded part is consolidated with an adhesive tape.

[0016] Now, the invention will be explained in detail with reference to
the drawings.

[0017] According to the present invention the open end of the bag is
closed in the following manner:

[0018] First, a product 1 having a rectangular shape is inserted into a
product container bag 2 until one of the product's sides wholly arrives
in the bottom of the bag (the left drawing of FIG. 1).

[0019] Then, the container bag 2 is folded over a line [the broken line
(a) in FIG. 1] that ran in the middle between the open end side 4 of the
bag 2 and that side edge 3 of the content (the product 1) which is
opposite to the side resting in the bottom of the bag 2, and then the bag
2 is further folded in the same direction as before over a line [the
broken line (b) in FIG. 2] that ran in the middle between said line (a)
and said side 3 of the pellicle case. Next, the bag 2 is finally folded
in the same direction over the side 3 of the pellicle case, and in order
to prevent the bag 2 from unfolding and re-opening, the folded part of
the bag is securely bandaged onto that part of the bag on which the
folded part of the bag is pressed, with an adhesive tape 5 (FIG. 4).

[0020] The position at which the adhesive tape 5 is applied can be
selected with prudence, and as shown in FIG. 4, it is preferable that the
adhesive tape 5 comes in the middle of the folded part of the bag. It is
also possible to use more than one strip of adhesive tape.

[0021] Incidentally, in the case shown in FIG. 4, the adhesive tape is
attached to extend in the depthwise direction of the bag 2, but it is
possible to attach the adhesive tape to extend in parallel to the crease
line (b).

[0022] As the bag is closed by being folded upon itself three folds, the
inner walls of the bag choke up the bag so that the external air is
stopped from entering the bag. Also, according to this folding method, in
order to gain a sufficient air-tightness, it suffices to fold the bag
only a few folds.

[0023] There is no particular limitation to the product container bag to
which the present invention is applicable, so long as the film surface of
the bag is smooth and is not formed with embossment or wrinkles; it is
preferable also, that such bag is made from a film having a thickness of
a certain range and is easy to fold and when folded the inner walls of
the bag attach themselves to one another by means of the bending force
created by the folding.

[0024] A recommended range for the thickness of the film from which the
bag is made is 50-200 micrometers.

[0025] There is no particular limitation as to the material of which the
product container bag is made, and examples include resins such as
polyethylene, nylon, polypropylene, and polyester, and it is possible to
use a bag made from a sheet of one of these resins of which at least one
of the faces is lined with: a metallic thin layer by means of vapor
deposition, or an anti-static layer; or it is possible to use a bag made
from a sheet which is a multilayer sheet consisting of one or more of the
above-mentioned resins.

[0026] There is no limitation as to the kind of the adhesive tape used to
consolidate the folded opening of the product container bag; however, it
is preferred that the tape has an anti-static characteristic so that when
the tape is peeled off the product container bag no static is created.
Among such adhesive tapes that are on the market, an example is
3250-Static Resistant Polypropylene Packaging Tape manufactured by NITTO
DENKO CORPORATION.

EMBODIMENTS

Embodiment 1

[0027] We will now describe examples of embodiment of the invention.

[0028] A rectangular bag made from a polyethylene film, having a thickness
of 70 micrometers, was prepared to contain a rectangular product. This
bag's opening was closed in a clean room in the following procedure.

[0029] Firstly, an encased pellicle, 6N2HF-EXN (this pellicle and the
container case are commercially available in unit from Shin-Etsu Chemical
Co., Ltd.), which is rectangular, was inspected for dust particles
sticking to it that were 10 micrometers or greater in size, in a dark
room by means of a 300,000-lux light condenser lamp. Then, the
rectangular product was inserted into the polyethylene bag until one of
the product's sides entirely reached the bottom of the bag.

[0030] Then, the bag was folded over a line that ran in the middle between
the open end side of the bag and that side of the pellicle case which is
opposite to the side resting in the bottom of the bag, and then the bag
was further folded in the same direction over a line that ran in the
middle between said line over which the bag was first folded and said
side of the pellicle case opposite to the side in the bag's bottom. Next,
the bag was folded again in the same direction along said side of the
pellicle case opposite to the side in the bag's bottom, and in order to
prevent the bag from re-opening the folded part of the bag was securely
bandaged onto that part of the bag on which the folded part of the bag
was temporarily pressed, with an adhesive tape. The manner in which the
adhesive tape was spanned is shown in FIG. 4, and the length of the
adhesive tape was about 40 mm. Incidentally, that end of the adhesive
tape 5 which extended beyond the bag was folded partially back in a
manner such that the adhesive-coated side of the tape stuck to itself
whereby a non-sticky tab was created.

[0031] This bag was left alone outside the clean room for a week. Then, it
was brought into the clean room and the container case was retrieved from
the bag, and it was inspected for particles sticking to it in the dark
room in the same manner as described above, and there was observed no
increase in the number of the particles that were 10 micrometers or
greater in size. Also the time it took to retrieve the container case
from the bag was three seconds.

[0032] In the similar manner this experiment was repeated changing the
number of the folding of the open end of the bag.

Comparative Example 1

[0033] A rectangular bag made from polyethylene film, having a thickness
of 70 micrometers, was prepared to contain a rectangular product and its
opening was closed in a clean room in the following procedure.

[0034] After counting the number of particles that were 10 micrometers or
greater in size sticking to the surface of the encased pellicle in the
same manner as above, the encased pellicle was inserted into the bag
until one of the case's side reached the bottom of the bag.

[0035] Then, the bag was sealed by heat along a line that ran in the
middle between the open side of the bag and that side of the case which
is opposite to the side resting in the bottom of the bag. This bag was
left alone outside the clean room for a week. Then, the bag was brought
into the clean room and was severed by scissors into two parts across a
line which is remoter from the mouth of the bag than the heat-sealed line
is, whereupon the encased pellicle was retrieved from the bag, and it was
inspected for particles sticking to it in the same dark room by the same
means.

[0036] Three particles were newly found on the surface of the case, which
are thought to be generated when the bag was severed.

[0037] Also the time it took to retrieve the encased pellicle was ten
seconds.

[0038] Table 1 shows different manners of closing of the polyethylene film
bag and their result in terms of the contamination,

[0039] From the results as shown in Table 1, it was learned that by
folding the opening part of the bag three or more times in the manner as
described above including the final folding over the side of the hard
case which is opposite to the side in the bottom of the bag and fixing
the folded part by an adhesive means, it is possible to securely to
prevent entrance of foreign materials into the bag. The more the folding
is repeated the higher the sealing effect of the bag becomes, but the
less easy the folding operation gets, and to fold the bag six times or
more is a feat and not practical. In the case where the opening of the
bag is heat-sealed or equipped with a fastener (zipper) or sealed with an
adhesive tape, the sealing effect after closing of the bag is secured
high; however, it has been the experience of the inventor that the
eventual use of a pair of scissors or a knife to open the heat-sealed bag
itself causes dust to occur, and it may be easy to open a zippered bag
but not so much so to close it, and it is troublesome to hermetically
close a bag with an adhesive tape, which results in a lengthy packing
time and low productivity.

INDUSTRIAL APPLICABILITY

[0040] By virtue of the method of the present invention, it is possible to
store a content air-tightly in a bag with ease without using an extra bag
or without modifying the bag, so that the method is applicable to packing
of various kinds of products, with the results such as secure packing,
easy retrieval, shorter manufacturing time, improved to product quality
and reduced cost.

EXPLANATION FOR REFERENCE NUMERALS

[0041] 1: product [0042] 2: container bag for the product [0043] 3: side
of the product opposite to the side at the bottom of the bag [0044] 4:
opening (of the bag containing the product) [0045] 5: adhesive tape